There are various web search engines available for users to search for information on the World Wide Web (WWW). Some search engines operate by storing information about web pages retrieved by a web crawler. A web crawler is an automated web indexing program that accesses a web site, traverses through the site by following the links present on the pages, and compiles an index of those links and the information available via the links. The compiled index is stored in a database for use by a search engine.
When a user enters a keyword search query via a client terminal into a web-based search engine, the search engine examines the index and compiles a set of search results that match the keyword query. The search results are usually transmitted back to the client computer for presentation through a browser application to the user in the form of an ordered listing of web pages, images, information, and other types of files.